Field of the Invention
This invention relates to a method for blocking of an eyeglass lens and to a blocking device for blocking of eyeglass lenses on blocking pieces having a blocking piece receiver which is located on a base body is to be attached to an eyeglass lens.
Description of Related Art
In general the term “eyeglass lens” in accordance with the invention is especially a plastic lens for eyeglasses.
The invention relates especially to a blocking device for blocking of eyeglass lenses or semi-finished eyeglass lenses on blocking pieces with a base body, with a blocking piece receiver which is located on the base body of the blocking piece which is to be attached to the eyeglass lens, and with a positioning unit which is located on the blocking device for alignment and holding of the eyeglass lens which is to be blocked, the blocking piece receiver and the positioning unit, which can be fixed on the eyeglass lens, being movable relative to one another along a lifting axis.
Furthermore, the invention relates especially to a method for blocking of a holding side of an eyeglass lens onto a coupling side of a blocking piece by means of plastic adhesive, the blocking piece being held in a blocking piece receiver and the eyeglass lens being movable relative to the blocking piece along one lifting axis.
German Patent Application DE 10 2008 023 093 A1 and corresponding U.S. Pat. No. 8,616,150 B2 already disclose a blocking device for blocking of eyeglass lenses on blocking pieces. This blocking device has a blocking piece receiver and a transport unit for positioning of the eyeglass lens which is to be blocked. For purposes of alignment of the relative position between the blocking piece and the eyeglass lens, the transport unit can be moved in five position-controlled axes of space, one translational lifting axis, a translational transverse axis and three axes of rotation which are aligned at right angles to one another, the axes of rotation being one pivoting axis and two pivot axes which thus image all three possible space-axes of rotation. The two pivot axes are intended to ensure a three-dimensional tilting of the eyeglass lens relative to the blocking piece. The eyeglass lens is pressed against the blocking piece via the translational lifting axis, leaving a defined gap. The eyeglass lens which is mechanically aligned relative to the blocking piece via the positioning unit is placed on the adhesive and by pressing is positioned at least indirectly against the blocking piece.
An end stop of the translational lifting axis is not reached in doing so. It is simply a predetermined holding position of the translational lifting axis within the framework of position control.
U.S. Pat. No. 2,660,011 discloses a horizontal alignment of a lens blank on a table, the lens blank being raised vertically after alignment and after pivoting the table away being lowered onto a blocking piece which is located underneath with heated adhesive.
The prior art does not allow optimum positioning of an eyeglass lens on an assigned blocking piece, especially when the holding side of the eyeglass lens facing the blocking piece and the coupling side of the blocking piece facing the eyeglass lens are matched to one another or are made complementary to one another and tilting for the optimum alignment is required. Furthermore the prior art does not allow optimum blocking, especially if the blocking means or adhesive requires a certain minimum thickness or optimum thickness, as is especially the case for plastic adhesives.